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<h1 id="allow-insecure-pop3imapsmtp-connections-without-starttls">Allow insecure POP3/IMAP/SMTP connections without STARTTLS</h1>
<div class="admonition attention">
<p class="admonition-title">Attention</p>
<p>Check out the lightweight on-premises email archiving software developed by iRedMail team: <a href="https://spiderd.io/">Spider Email Archiver</a>.</p>
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<div class="toc">
<ul>
<li><a href="#allow-insecure-pop3imapsmtp-connections-without-starttls">Allow insecure POP3/IMAP/SMTP connections without STARTTLS</a><ul>
<li><a href="#allow-insecure-pop3imap-connections">Allow insecure POP3/IMAP connections</a></li>
<li><a href="#allow-insecure-smtp-connection-on-port-25">Allow insecure SMTP connection on port 25</a></li>
</ul>
</li>
</ul>
</div>
<p>With default iRedMail setting, all clients are forced to use POP3/IMAP/SMTP
services over STARTTLS for secure connections. If your mail clients
try to access mailbox via protocol POP3/IMAP without TLS support, you will
get error message like below:</p>
<pre><code>Plaintext authentication disallowed on non-secure (SSL/TLS) connections
</code></pre>
<p>This tutorial describes how to allow insecure connection for daily use.</p>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>If you just have 1 or few network devices like printer, firewall need to
send email with insecure connection, please follow this tutorial instead:
<a href="./additional.smtp.port.html">Allow internal network devices to send email with insecure connection</a>.</p>
</div>
<h2 id="allow-insecure-pop3imap-connections">Allow insecure POP3/IMAP connections</h2>
<p>If you want to enable POP3/IMAP services without STARTTLS for some reason
(again, not recommended), please update below two parameters in Dovecot config
file <code>/etc/dovecot/dovecot.conf</code> and restart Dovecot service:</p>
<ul>
<li>on Linux and OpenBSD, it's <code>/etc/dovecot/dovecot.conf</code></li>
<li>on FreeBSD, it's <code>/usr/local/etc/dovecot/dovecot.conf</code></li>
</ul>
<pre><code>disable_plaintext_auth=no
ssl=yes
</code></pre>
<p>Again, it's strongly recommended to use only POP3S/IMAPS for better security.</p>
<p>Default and recommended setting configured by iRedMail is:</p>
<pre><code>disable_plaintext_auth=yes
ssl=required
</code></pre>
<h2 id="allow-insecure-smtp-connection-on-port-25">Allow insecure SMTP connection on port 25</h2>
<p>Please comment out lines below in Postfix config file <code>/etc/postfix/main.cf</code>
and reload or restart Postfix service:</p>
<pre><code>smtpd_sasl_auth_enable = yes
smtpd_sasl_security_options = noanonymous

# force all clients to use secure connection through port 25
#smtpd_tls_auth_only=yes
</code></pre><div class="footer">
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